Diagnosis of a physiological condition of a subject can include various physiological factors. Generally, impedance changes over time can be measured to monitor and identify a physiological condition. The impedance changes over time of a particular electrode configuration or a vector can have many contributing factors. These factors can contribute to impedance signal changes measured by a device. The contributing factors can include changes in lung resistivity, changes in blood resistivity, changes in heart muscle resistivity, changes in heart or lung volumes, or other physiological factors. Measuring changes in impedances can be used to indicate changes in physiological factors. However, not all of the contributing physiological impedance factors are indicative of important physiological change, which might require clinical intervention. Isolating a particular physiological factor or a combination of physiological factors that contribute to the change in impedances can be difficult.